"The reserve replacement in 2000 demonstrates the continued success of our long-term strategy to focus on high-potential oil and gas exploration and production provinces," said Charles R. Williamson, Unocal chief executive officer.

During 2000, the company added reserves of 168 million BOE from discoveries/extensions and improved recovery. The company also added 143 million BOE from acquisitions. The increases were offset partially by the sale of 19 million BOE and price-related revisions, which reduced reserves by a net 46 million BOE.

Unocal's North America operations replaced 143 percent of production with new reserves. Unocal booked more than 52 million BOE from discoveries, extensions and improved recovery and 94 million BOE from acquisitions. The year-end 2000 reserves include 100 percent of the reserves of Pure Resources, Inc., a 65-percent-owned subsidiary. No reserves were booked for deepwater Gulf of Mexico discoveries.

Unocal's international operations replaced 129 percent of production. This reflected the effects of 52 million BOE in negative price-related revisions under the terms of certain production-sharing contracts (PSCs). The negative price revisions are the result of higher crude oil and natural gas prices that reduce entitlement volumes attributable to the future recovery of costs.

In addition to proved reserves, Unocal has significant discovery volumes in the deepwater Gulf of Mexico, as well as in Indonesia, Bangladesh, Vietnam, Azerbaijan, Myanmar and Thailand that await either market development or official project sanction.

For the year, Unocal's worldwide finding, development and acquisition (FD&A) costs for new reserves were $7.77 per BOE (see table). Worldwide finding and development (F&D) costs were $9.31 per BOE.

Change in reserve reporting

Unocal will be changing its reporting method for reserves and production in Indonesia and the Democratic Republic of Congo. Starting in 2001, all production-sharing contracts will be reported on the economic interest method, which excludes host-country shares. The effect of this change on Unocal's current reserves and FD&A costs is noted in the attached tables.

This news release contains certain forward-looking statements about proved reserves. These statements are not guarantees of future performance. Proved reserves, as defined by the U.S. Securities and Exchange Commission (SEC), are the estimated quantities of crude oil, natural gas and natural gas liquids that geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic and operating conditions. Proved reserve quantities exclude royalty interests owned by others. The statements are based upon Unocal's current expectations and beliefs and are subject to a number of known and unknown risks and uncertainties that could cause actual results to differ materially from those described in the forward looking statements. Actual results could differ materially as a result of factors discussed in Unocal's 1999 Form 10-K and other reports report filed with the SEC. Unocal undertakes no obligation to update the information in this news release.

Estimated proved reserves of crude oil, condensate and natural gas

Crude Oil MMbbls

Natural Gas BCF

Oil Equivalent MMBOE

As of December 31, 1999 (1) (2)

550

6618

1653

Discoveries and Extensions

62

581

159

Improved Recovery

3

38

9

Revisions

7

(232)

(32)

Purchases

82

364

143

Sales

(7)

(74)

(19)

Production (1)

65

755

191

As of December 31, 2000 (1) (3)

632

6540

1722

Estimated proved reserves by geographic area (MMBOE)

North America

International

Total

Lower 48

Equity Interests (4)

Alaska

Canada

Far East

Other

Worldwide

As of Dec. 31, 1999 (1) (2)

341

20

111

115

888

178

1653

Discoveries and Extensions

36

1

3

9

91

19

159

Improved Recovery

2

0

1

0

6

0

9

Revisions

6

4

14

(14)

(28)

(14)

(32)

Purchases

87

4

0

3

47

2

143

Sales

(12)

(1)

0

(6)

0

0

(19)

Production (1)

61

3

19

13

84

11

191

As of Dec. 31, 2000 (1) (3)

399

25

110

94

920

174

1722

(1) Includes host countries' shares for Indonesia and Democratic Republic of Congo:

At Dec. 31, 1999

117

2

119

At Dec. 31, 2000

147

3

150

Proved reserves, not including host countries' shares, were 1,534 MMBOE and 1,572 MMBOE for the year-end 1999 and 2000, respectively. Production for year 2000, not including host countries' shares, was 176 MMBOE. Starting in 2001, host countries' shares will be excluded from reported reserves and production.

(2) Included in the year-end 1999 Lower 48 and Canada reserves were 24 MMBOE and 48 MMBOE, respectively, attributable to outstanding minority interests in consolidated subsidiaries.

(3) Included in the year-end 2000 Lower 48 reserves were 69 MMBOE attributable to outstanding minority interests in consolidated subsidiaries.

(4) Proportional interests in reserves of equity investees

Note for the above, natural gas is converted at a ratio of 6 MCF to one barrel of oil.